Are trauma-related beliefs associated with psychosis symptoms? A systematic review and meta-analysis

Trauma-related beliefs are theorized to contribute to the development and maintenance of psychosis symptoms. However, the evidence for this proposal has yet to be systematically reviewed. This article is the first to synthesize and meta-analyze studies examining associations between trauma-related beliefs and psychosis symptoms, including hallucinations, delusions, paranoia, and negative symptoms. A systematic database search of Medline, PsychINFO, Embase, Web of Science, CINHAL, and Cochrane identified a total of 15 articles that met the inclusion criteria for systematic review and 11 articles which met the inclusion criteria for meta-analysis. Separate random-effects meta-analyses were conducted for each psychosis symptom. Meta-analytic findings demonstrated a small to moderate association between trauma-related beliefs and hallucination severity (k = 7, r = 0.25, 95% CI 0.10-0.39), a moderate to large association with delusion severity (k = 8, r = 0.43, 95% CI 0.31-0.54), and large association with paranoia severity (k = 4, r = 0.58, 95% CI 0.49-0.66). Narrative synthesis findings indicate that evidence for an association between negative symptoms and trauma-related beliefs was inconclusive. The meta-analytic findings provide support for an association between trauma-related beliefs and positive psychosis symptoms. This provides evidence suggesting trauma therapies for psychosis that target these beliefs may improve distressing psychosis. However, further research adopting longitudinal designs and controlling for confounders is required to better establish causality, including mediation analysis of therapy trials.